Files are first encrypted and then transferred directly on a SSL over μTP connection.
Each device must be setup with a group name and group password: this pair is used to create an unique encryption key used for signaling (not for the file encryption) so devices in the same network but belonging to different users cannot talk to each other.
You can send files from within the app or, on mobile, share them from other apps.
The app requires a subscription on mobile, but the money is taken only after a week of trial unless the subscription is canceled first.
Subscriptions are managed by Google & Apple.
